I was shooting my 300 WM yesterday and ran into some pressure issues with the factory stuff. I had some pretty stiff bolt lift. The brass didn't show any signs. The primers were fairly flat.

Just wondering if this is something common.

Graybird,

Is it a Weatherby or Winchester mag?

What is the make of rifle? (custom chamber or factory?)

Factory chamber in 300 Win Mag, Ruger M77 mark II.

Load I was shooting was the Nosler Trophy Grade 190 gr LR AccuBond.

I have a friend with a new .300 WSM that is having stuck bolt problems and pierced, flattened primers that fall out of the cases. Federal Vital Shock X bullets...factory ammo.

quote:

I was shooting my 300 WM yesterday and ran into some pressure issues with the factory stuff. I had some pretty stiff bolt lift. The brass didn't show any signs. The primers were fairly flat

Controlling pressure is a difficult thing for cartridge companies. First of all, your rifle is different from their pressure barrel and that does make a huge difference. Secondly, you bought a Magnum, you expect magnum performance and that comes with huge amounts of powder burnt at high pressures. It would be rather unlikely to experience pressure problems with something so powderpuff as 148 LWC loads in the 38 Special as target shooters want a load with the least recoil.

This was written by Unclenick on another forum, and it might help explain why factory ammunition might produce high pressures in your rifle. And it has to do with pressure standards and what is acceptable by SAAMI:

The SAAMI system, when you look at it in detail, actually includes quite a bit of wiggle room for error. For example, a .308 Winchester maximum average pressure (MAP) is the average of the peak values for a 10 round sample taken when the ammunition is newly loaded. That average is allowed to go up to 66,000 psi for a 10 round sample pulled at any future time as the lot ages (maximum probable sample mean, or MPSM). The Maximum Extreme Variation (MEV) is the pressure a worst case individual round is allowed to reach, and for .308 Winchester the MEV is ±12,800 psi. So the maximum pressure for a new non-proof round will be:

62,000 psi + 12,800 psi = 74,800 psi.

That's not quite up to proof pressure (82,000-92,000 psi for .308 Win), but you can see how much wiggle room there is. In a .308 Win firing Varget under the 175 grain SMK, QuickLOAD says that would take a charge error about 5.8% too high to reach the upper side MEV, which is over 2 grains of powder. I know some handloader's powder measures are a little irregular with stick powders, but not that irregular.

You can to this webpage and read some very good information on pressure standards:

Cartridge Pressure Standards

http://kwk.us/pressures.html

So given that your ammunition may have been on the high side of SAAMI standards and your rifle may have a tight bore, etc, something different from the pressure gage, hey, bad stuff can happen.

But, let's understand something else, SAAMI standards are voluntary and compliance is voluntary. There is no outside agency ensuring that any ammunition company even follows its own in house standards and it is entirely possible that the ammunition lot you have was outside of SAAMI recommended limits. We see this all the time with industry, shipping non conforming material because scrapping it reduces corporate profits. As an example, just Google “Meat Recalls”. The meat industry has limited Government oversight and legal liability (the food industry hardly ever pays for poisoning people) and yet you will see many examples of where the meat industry knowingly shipped bad and rotting meat, and it has to be recalled.

http://www.cnn.com/2014/02/08/us/beef-product-recall/
http://www.fsis.usda.gov/wps/p...all-013-2014-release
http://www.foodsafetynews.com/sections/food-recalls/

Has happened all over the world for many years, with just about all designations of cartridges.

I once had a matched pair or Holland & Holland bolt actions in .275 H&H. Kynoch factory ammo worked fine in one of them and would blow primers and freeze the bolt in the other. Easiest probable solution? Try some other makes of ammo, or even different bullet weights (and ogive shapes) of the same brand.

I have a Savage 300 WSM that won't handle Winchester factory loads.

I shoot 180 grainers outta my 30-378, 98.5 grains RL-22 gives me 3280 on chrono. So I shoot some Weatherby ammo and get a tight bolt, almost 3600 on the chrono. I called Weatherby and they checked lot number, said it was recalled, send it to us. Happens from time to time I guess.

It has been so long since I've shot factory ammo, I was surprised at the pressure signs I was seeing.

Had a Winchester Model 70 CF action in 7STW that would lock the bolt up with factory Remington ammo.

Yup, I had a 300WM lock up with Winchester Failsafes. Had to beat the bolt handle with a rawhide mallet to get the action open. Sent the bullets back to Winchester to be checked. They said there was no problem with them.

Hirtenberger ammo is so bad in this regars.

I have so much ammo of different calibers, by Hirtenberger, given to me by people who had pressure problems with it.